An autopsy case of diffuse malignant mesothelioma of the pericardium

A report is presented of an autopsy case of a 71-year-old Japanoae man with a diffuse malignant epithelial mesothelioma of the pericardium with massive pericardlal effusion and a thickened perkardlum. He had no history of exposure to asbestos. He suffamd severe heart failure and later died. Autopsy revealed that tho tumor had developed over the pericardlum. Microscopically, the tumor cells were arranged In an epithelial form, and histochemically. the cytoplasm of these cells contained glycogen and hyaluronlc acid. The tumor tissue showed immunohlstochemical positivity for cytokeratin, epithelial membrane antigen, vimentln, cancer antigen 125, thrombomodulin. mesothellal antigen, muscle actin and human milk fat globule. In contrast, all the tumor cells were negative for human carcinoembryonic antigen and epithelial antigen. ultrastructurally. the tumor cells had long, thin microvilli, abundant lntermedlate filaments, intracyto-plasmic lumina and long deamosomes. It Is considered that the patient had a typical malignant epithelial mesothelioma of the pericardium.